Spaced wall combustion apparatus



May 22, 1956 F. R. BlcHowSKY ET AL 2,746,249

SPACED WALL COMBUSTION APPARATUS Filed Sept. 14, 193

am 4M United States Patent O SPACED WALL COMBUSTION APPARATUS Francis R. Bichowsky, Toledo, Ohio, and Robert H. Carileld, Washington, D. C.

Application September 14, 1936, Serial No. 100,686

1 Claim. (Cl. 60--39.46)

(Granted under Title 35, U. S. Code (1952), sec. 266) This invention relates to apparatus for developing high power in a restricted space, and more particularly to the use of hydrogen peroxide as a source of oxygen to support combustion, and to the combination therewith of a liquid catalyst to accelerate the decomposition of the hydrogen peroxide to free the oxygen.

Among the several objects of this invention are:

To provide means for burning fluid fuel in the presence of oxygen delivered from hydrogen peroxide;

To provide a catalyst that will decompose the hydrogen peroxide to free the oxygen therefrom;

To provide a combustion pot in which fuel may be eiciently burned by use of the agencies above mentioned;

To provide a power plant of high output and small space requirements.

Other objects will become apparent to those skilled in this art from the description following, in connection with the drawing wherein:

Fig. l is a schematic diagram of a system embodying the principles of the present invention;

Fig. 2 is a longitudinal section through a combustion pot and the connections thereto for practicing our invention.

While the present disclosure is, for purpose of illustration, based upon combustion apparatus particularly adapted to use in submarine torpedoes, it is to be understood that the drawings and specication are by way of description and not of limitation. I

The power plant of a submarine torpedo comprises a combustion pot wherein are produced gases at high temperature and pressure which are utilized in some form of engine to drive the torpedo through the water. Due to the limited space available in a torpedo, the generating plant must have the highest possible output and ordinarily comprises some means for burning a fuel, usually alcohol, in a supporter of combustion that may be air or oxygen carried under high pressure in a tank. However, there are serious objections to air and oxygen in that a heavy container must be provided to withstand the high pressures necessary to carry the requisite volume of air, and oxygen alone forms explosive mixtures with lubricants when under high pressure. The present invention makes it possible to carry an adequate supply of a source of oxygen in a light container.

Hydrogen peroxide is a clear liquid miscible in all proportions with water. lt decomposes exothermally with the iiberation of about 23,000 calories per gram-molecule. Nevertheless, aqueous solutions thereof may be stabilized by various known methods so that solutions of 30% are handled and stored commercially in large quantities. We have found that such aqueous solutions can be prepared and safely stored at concentrations as high as 70%.

Our investigations have shown that hydrogen peroxide in solutions of strengths varying from 30% up to 60% may be utilized as a source of oxygen to support combustion of fuel, and that a strength of 45% by weight gives very satisfactory results. The heat produced by 2,746,249 Patented May 22, 1956 ICC the combustion of the fuel, added to the heat of exothermic decomposition of the peroxide, is suicient to convertthe products of combustion, plus the water in which the peroxide is dissolved, plus the water produced by its'v decomposition, into a mixture of clear gas consisting mostly of steam, the temperatures varying from 430 F. to over 2,000o F. depending on the original concentration of the peroxide and on the construction of the combustion chamber.

For instance, in one case, ethyl alcohol and a 50% solution of hydrogen peroxide were forced into a combustion chamber at a pressure of 450 pounds per square inch. The rates of ow were 3.75 pounds per minute of fuel and 12.5 pounds per minute of peroxide solution, which produced a temperature of 1200 F. upon burning. The products of combustion were allowed to issue into the air through a suitable expansion nozzle, and were found to be colorless and clear. The reaction due tothe jet of gases was measured and found to indicate a rate of energy production equal to 98 horsepower.

Although, under certain circumstances, it may be possible to initiate decomposition of the peroxide by the heat of the combustion started by a pyrotechnic igniter or other outside source of heat, we have found that the most satisfactory method of initiating and maintaining steady combustion is by injecting into the stream of peroxide solution, just as it enters the combustion vessel, a small quantity of a chemical catalyst in aqueous solution, for which purpose a number of materials are available. Among the substances that have been tried and found satisfactory are colloidal cobaltous oxide in ammonia and also potassium or sodium permanganate as a 12% solution in water. The permanganate solution in a proportion of one part used with l0 to 20 parts of peroxide solution will decompose the latter in one second into oxygen, hot water, and steam. Though not all colloidal solutions are effective catalysts for this purpose, all that have so far been tried and found satisfactory are colloidal solutions of metals or of metallic oxide. These oxides may either be introduced as such into the original solution or they may be formed from the solution upon contact with hydrogen peroxide. The latter is the case with the solutions of permauganate above mentioned, the effective catalytic agent being colloidal manganese dioxide formed by reaction with the hydrogen peroxide.

Although the combustion may be effected in a variety of way, we have found that the apparatus and method now to be set forth are very satisfactory.

As is shown schematically in Fig. l, the combustion vessel 3 is connected to a supply of fuel 4, a body of hydrogen peroxide solution 5 and a supply of catalyst solution 6, the latter two being so introduced into the combustion device as to be intermingled, the pressure requisite for feeding the various substances to the combustion device being derived from a container 7 lled with air or gas under pressure. It is to be understood that any other suitable means, such as pumps, may be used to furnish the pressure required in the feed lines.

Fig. 2 shows one embodiment of combustion apparatus for practicing the present invention. The combustion vessel proper comprises an outer Wall 3 and spaced therefrom an inner Wall 9 that defines the combustion chamber, the two walls being joined together at their lower edges as shown at 10. Secured to, or integral with, the upper end of the wall 9 is an end portion 11 provided with perforations 12 that communicate with the combustion chamber and with the space between walls 8 and 9. The fuel is introduced through pipe 13 into a space inclosed by the wall 14 and issues therefrom into the combustion chamber through apertures 15, the axes of the perforations 12 and 15 being so disposed that uids passing through the two sets of apertures will be thoroughly commingled in the combustion chamber, with the fuel stream separated from the wall 9 by a screen of spray projected through the apertures 12 to protect the wall 9 somewhat from the very high temperature of combustion attained. Hydrogen peroxide solution is introduced through pipe 16 and immediately adjacent thereto the catalyst solution is introduced through pipe 17 to secure thorough mixing of the two solutions. 1t is apparent that the space between walls 8 and 9 will be occupied by a mixture of the peroxide solution and the catalyst solution and reaction between the two will take place, resulting in the liberation of oxygen as is indicated by the rising stream of bubbles 18. The oxygen, together with the Water used in making the solutions and that which results from decomposition of the peroxide, will be forced through the apertures 12 in the form of a tine spray which will mingle with the spray of fuel, resulting in the combustion of the fuel and the conversion of the associated water to steam. It is necessary that steam be generated to absorb some of the heat that is liberated, otherwise temperatures destructive to the wall of the combustion chamber would be reached and the gases of combustion would be too hot for utilization in an engine. A further advantage is that the steam increases the volume of the gaseous products. The gases from the combustion chamber are carried through a pipe 19 to suitable nozzles 2t) where they are expanded and the heat energy is converted into mechanical energy.

Although any suitable means of igniting the mixture of fuel and the supporter of combustion may be used, we have shown, by way of illustration, a pyrotechnic igniter 21 that may be tired simultaneously with the beginning of supply of fuel into the combustion chamber.

The body of aqueous solution between the walls 8 and 9 absorbs heat that is transmitted through wall 9 and returns it to the combustion chamber, thus preventing, to a great extent, the loss of energy by radiation into the space around the combustion device.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

I claim:

A combustion device, comprising a vessel having two spaced walls joined together at one end of the vessel and with their opposite ends closed, means to introduce a spray of fuel inside the inner one of said walls at the said opposite end thereof, the said inner wall perforated at the said closed end to permit the passage of uid fIom between said walls into the space within said inner wall in the form of a spray to mingle with the spray of said fuel, means to introduce into the space between said walls adjacent the junction of said Walls a fluid that carries a supporter of combustion, means adjacent the said means to introduce into said space between the walls a uid to interact with the rst mentioned ,fluid to render said supporter of combustion more readily available to burn said fuel, and means to ignite the combustible mixture within said inner wall.

References Cited in the tile of this patent UNITED STATES PATENTS 1,108,668 Nedoma Aug. 25, 1914 1,154,609 Bruniquel Sept. 28, 1915 1,459,482 Underwood June 19, 1923 1,506,323 ONeill Aug. 26, 1924 1,531,475 Brandt Mar. 31, 1925 2,168,313 Bichowsky Aug. 8, 1939 FOREIGN PATENTS 492,294 France Ian. 11, 1916 OTHER REFERENCES Comprehensive Treatise on Inorganic & Theoretical Chemistry, vol. 1, by Mellor, published 1922 by Longmans, Green and Co., London, England, pp. 937 and 944.

Catalysis in Theory and Practice, by Rideal and Taylor, published 1926, by MacMillan & Co., Ltd., London, England, p. 386. 

